Nonaqueous electrolyte secondary battery and producing method thereof

Abstract

The present invention provides for a nonaqueous electrolyte secondary battery and a producing method therefor, in which a grooved portion provided in an upper portion of the outer casing of the nonaqueous electrolyte secondary battery protrudes toward the inner portion of the outer casing, a group of electrodes being housed in the outer casing, a positive electrode and a negative electrode being wound in a spiral manner while facing each other through a separator in the group of electrodes, and a sealing member is placed on the upper portion of the grooved portion through insulated packing to seal the opening of the outer casing in an airtight manner, and whereby a circular insulating plate 10 provided with an arced opening 12 and cut portions 13 and 14 is arranged between the upper portion of the group of electrodes and the lower surface of the grooved portion, the cut portions 13 and 14 extending from end portions 12 a and 12 b of the opening 12 , and the inner peripheral side of the cut portions 13 and 14 of the circular insulating plate is raised from the outer peripheral side of the cut portions 13 and 14 . Such insulating plate does not adversely affect the injection property of the electrolytic solution used in producing the nonaqueous electrolyte secondary battery as to provide it with excellent battery performance and excellent productivity.

1. A nonaqueous electrolyte secondary battery in which a grooved portion provided in the upper portion of the outer casing thereof protrudes toward the inner portion of the outer casing, a group of electrodes being housed in the outer casing, a positive electrode and a negative electrode being wound in a spiral manner while facing each other through a separator in the group of electrodes, and a sealing member is placed on the upper portion of the grooved portion through insulated packing to seal the opening of the outer casing in an airtight manner,
 wherein a circular insulating plate provided with an opening and a cut portion is arranged between the upper region of the said group of electrodes and the lower surface of the said grooved portion, the said cut portion extending from an end portion of the opening, and an inner peripheral side of the cut portion of the circular insulating plate is raised from an outer peripheral side of the cut portion. 
 
     
     
       2. A nonaqueous electrolyte secondary battery according to  claim 1 , wherein the opening of the circular insulating plate is formed in the shape of a semicircular arc, and the inner periphery of the opening is formed in such manner as to cover a portion corresponding to the central axis region of the group of electrodes. 
     
     
       3. A nonaqueous electrolyte secondary battery according to  claim 2 , wherein the cut portion of the circular insulating plate is formed so as to extend radially toward both sides from end portions of the said semicircular arced opening along the outer periphery of the opening. 
     
     
       4. A nonaqueous electrolyte secondary battery according to  claim 1 , wherein the cut portion of the circular insulating plate is formed so as to linearly extend from one end portion of the inner periphery of the said semicircular arced opening. 
     
     
       5. A nonaqueous electrolyte secondary battery according to  claim 1 , wherein a tubular center pin is provided in the central axis region of the said group of electrodes. 
     
     
       6. A nonaqueous electrolyte secondary battery producing method in which a sealing member is placed in an upper portion of the outer casing thereof through insulated packing, a group of electrodes being housed in the outer casing, a positive electrode and a negative electrode being wound in a spiral manner while facing each other through a separator in the group of electrodes, and the opening of the outer casing is sealed by caulking to produce a nonaqueous electrolyte secondary battery,
 the nonaqueous electrolyte secondary battery producing method comprising: 
 a housing step, whereby the group of electrodes is housed in the outer casing after arranging a circular insulating plate provided with a semicircular arced opening and a cut portion, the semicircular arced opening being located in the upper region of the group of electrodes, and the cut portion extending from an end portion of the semicircular arced opening; 
 a grooving step, whereby a grooved portion is formed at approximately the same height from the outer bottom surface of the outer casing where the said circular insulating plate is arranged in the upper portion of the outer casing in which the group of electrodes is housed, and the grooved portion protrudes toward the inner portion of the outer casing from the outer portion thereof; and 
 a sealing step of caulking a sealing portion of the outer casing after a sealing member is placed in the upper portion of the grooved portion through insulated packing. 
 
     
     
       7. A nonaqueous electrolyte secondary battery producing method according to  claim 6 , wherein the circular insulating plate is formed such that the inner periphery of the opening thereof covers a portion corresponding to the central axis region of the group of electrodes. 
     
     
       8. A nonaqueous electrolyte secondary battery producing method according to  claim 6 , wherein the circular insulating plate is formed such that the cut portion thereof extends radially toward both sides from end portions of the semicircular arced opening along the outer periphery of the said opening. 
     
     
       9. A nonaqueous electrolyte secondary battery producing method according to  claim 6 , wherein the circular insulating plate is formed such that the cut portion thereof linearly extends from one end portion of the inner periphery of the semicircular arced opening. 
     
     
       10. A nonaqueous electrolyte secondary battery producing method according to  claim 6 , wherein a tubular center pin is provided in the central axis region of the group of electrodes.